text: /*
  ** Copyright 2006, The Android Open Source Project
  **
  ** Licensed under the Apache License, Version 2.0 (the "License"); 
  ** you may not use this file except in compliance with the License. 
  ** You may obtain a copy of the License at 
  **
  **     http://www.apache.org/licenses/LICENSE-2.0 
  **
  ** Unless required by applicable law or agreed to in writing, software 
  ** distributed under the License is distributed on an "AS IS" BASIS, 
  ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
  ** See the License for the specific language governing permissions and 
  ** limitations under the License.
  */
  
  #include <cutils/sockets.h>
  
  #include <errno.h>
  #include <fcntl.h>
  #include <stddef.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  
  #include <sys/socket.h>
  #include <sys/select.h>
  #include <sys/types.h>
  #include <netinet/in.h>
  #include <netdb.h>
  
  static int toggle_O_NONBLOCK(int s) {
      int flags = fcntl(s, F_GETFL);
      if (flags == -1 || fcntl(s, F_SETFL, flags ^ O_NONBLOCK) == -1) {
          close(s);
          return -1;
      }
      return s;
  }
  
  // Connect to the given host and port.
  // 'timeout' is in seconds (0 for no timeout).
  // Returns a file descriptor or -1 on error.
  // On error, check *getaddrinfo_error (for use with gai_strerror) first;
  // if that's 0, use errno instead.
  int socket_network_client_timeout(const char* host, int port, int type, int timeout,
                                    int* getaddrinfo_error) {
      struct addrinfo hints;
      memset(&hints, 0, sizeof(hints));
      hints.ai_family = AF_UNSPEC;
      hints.ai_socktype = type;
  
      char port_str[16];
      snprintf(port_str, sizeof(port_str), "%d", port);
  
      struct addrinfo* addrs;
      *getaddrinfo_error = getaddrinfo(host, port_str, &hints, &addrs);
      if (*getaddrinfo_error != 0) {
          return -1;
      }
  
      int result = -1;
      for (struct addrinfo* addr = addrs; addr != NULL; addr = addr->ai_next) {
          // The Mac doesn't have SOCK_NONBLOCK.
          int s = socket(addr->ai_family, type, addr->ai_protocol);
          if (s == -1 || toggle_O_NONBLOCK(s) == -1) break;
  
          int rc = connect(s, addr->ai_addr, addr->ai_addrlen);
          if (rc == 0) {
              result = toggle_O_NONBLOCK(s);
              break;
          } else if (rc == -1 && errno != EINPROGRESS) {
              close(s);
              continue;
          }
  
          fd_set r_set;
          FD_ZERO(&r_set);
          FD_SET(s, &r_set);
          fd_set w_set = r_set;
  
          struct timeval ts;
          ts.tv_sec = timeout;
          ts.tv_usec = 0;
          if ((rc = select(s + 1, &r_set, &w_set, NULL, (timeout != 0) ? &ts : NULL)) == -1) {
              close(s);
              break;
          }
          if (rc == 0) {  // we had a timeout
              errno = ETIMEDOUT;
              close(s);
              break;
          }
  
          int error = 0;
          socklen_t len = sizeof(error);
          if (FD_ISSET(s, &r_set) || FD_ISSET(s, &w_set)) {
              if (getsockopt(s, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
                  close(s);
                  break;
              }
          } else {
              close(s);
              break;
          }
  
          if (error) {  // check if we had a socket error
              // TODO: Update the timeout.
              errno = error;
              close(s);
              continue;
          }
  
          result = toggle_O_NONBLOCK(s);
          break;
      }
  
      freeaddrinfo(addrs);
      return result;
  }
  
  int socket_network_client(const char* host, int port, int type) {
      int getaddrinfo_error;
      return socket_network_client_timeout(host, port, type, 0, &getaddrinfo_error);
  }
  